A strategy for controlling groundwater depletion in the Sa'dah Plain, Yemen

Water Resources Development, Vol. 15, No. 3, 349± 365, 1999

A Strategy for Controlling Groundwater Depletion in

the Sa’dah Plain, Yemen

RAFIK A. AL-SAKKAF, YANGXIAO ZHOU & MICHAEL J. HALL

International Institute for Infrastructural, Hydraulic and Environmental Engineering, PO Box

3015, 2601 DA, Delft, The Netherlands

ABSTRACT Over-exploitationof the groundwater resources is the major problem lead-ing to groundwater depletion in the Sa’dah Plain, one of the major semi-arid highlandbasins of Yemen. Groundwater-irrigatedagriculture is the chief economic activity in thePlain. Consequently, depletion places socioeconomic development in jeopardy. Owing tothe lack of institutional arrangements and management instruments, governmentintervention is not likely to alleviate the crisis. One non-governmental approach thattakes advantage of the existing local sociopolitical structure and customary law wouldbe to adopt an annual abstractionquota. Approachingthe crisis at a grass-rootslevel andrelying on the conformity of the local citizens with customary law are the maincharacteristics of this strategy, the optimum objective of which is sustainable utilizationof water resources.

Introduction

The Sa’dah Plain is one of the intermontane plains of Yemen which illustrates allthe different manifestations of groundwater problems in the country. It is a basinin seclusion as a closed water system. The Plain is situated in the WesternHighlands of Yemen at a distance of about 250 km north of the Capital City ofSana’a in the centre of the Governorate of Sa’dah. The administrative centre ofthe Governorate is Sa’dah Town, which is located in the south-east. The areaforms part of the catchment of Wadi Marwan, a tributary of Wadi Najran whichdrains into the Rub’ Al-Khali Desert (The Empty Quarter) (Figure 1). With anelevation ranging from 1840 to 2050 metres above mean sea level (m 1 msl), thePlain slopes with a gentle gradient ranging between 0.2% and 0.5% towards thesouth-east where it collects in the stream channel of Wadi Marwan ¯ owing in anorthern direction into Wadi Najran. The Plain is surrounded by dissected,mostly steep and bare mountains up to an elevation of 2750 m 1 msl.

According to Koppen classi® cation the area is mountainous semi-arid. Rainfallis sporadic and scanty and storms are usually short, intense and local. Theaverage annual rainfall within the Plain for the period 1983± 92 was about135 mm with a standard deviation of 50 mm. There is no evidence of severedroughts in this period. In general there are two peaks of rainfall during theyear: March± May and July± August. April is the month with the highest read-ings. Evaporation far exceeds precipitation during most of the year. Potential

0790-0627/99/030349± 17 $7.00 Ó1999 Taylor & Francis Ltd

350 R. A. Al-Sakkaf et al.

Figure 1. The Sa’dah Plain area.

evapotranspiration is very high in the area owing to its arid nature; the annualvalue is about 2280 mm.

The population of the area was estimated to be around 200 000 inhabitants in1996. In the late 1970s, the directions of socioeconomic development in thecountry emphasized the development of irrigated agriculture. To boost the ruraleconomy of the Plain, groundwater development was started to supply water foragriculture. Ever since, irrigated agriculture has replaced rainfed agriculture asthe major economic activity in the area. Citrus crops and vegetables are the mainagricultural products. Livestock rearing and agroforestry are marginal practices,although the potential for developing these activities is very high.

The major problem in the Plain is the over-exploitation of the groundwaterresources, leading to groundwater depletion. As a result of scanty annualprecipitation, ¯ ow in the wadis that drain into the Plain is rarely observed.Consequently, replenishment of groundwater is limited. In spite of that, morethan 2500 wells tap the aquifer with an annual rate of abstraction that farexceeds the recharge rate (DHV, 1993a). Approximately 98% of the availablewater in the Plain is claimed by agriculture. Coupled with that is the inef® cientuse of groundwater in irrigation. The sandstone aquifer is the only reliablesource of water in the Sa’dah Plain. Development of an alternative conventionalsource of fresh water is not possible and it is not viable to transport water from

Controlling Groundwater Depletion 351

one basin to another in the Western Highlands of Yemen. Indeed, all basins inthe Western Highlands of Yemen suffer from water scarcity and groundwaterdepletion. In the case of Yemen, the only feasible substitute for depletedgroundwater is desalinated seawater. The major constraint is the tremendouseconomic cost of pumping the water to altitudes higher than 2000 m. Thisalternative may be suitable for coastal areas for supplying domestic and munici-pal water. As for the Highland Plains, this is not conceivable in the foreseeablefuture. Not only has geography ruled out the possible use of desalinated waterfor the Sa’dah Plain, but also the purpose of using the resource for irrigation isnot viable. The gravity of the water crisis in the Sa’dah Plain is deepening.Groundwater is being depleted to such an extent that socioeconomic develop-ment is threatened by the cessation of irrigated agriculture. The signs of theseverity of the crisis have manifested themselves in the total abandonment of avillage in the area by its inhabitants. The wells went dry and the people had noother choice but to leave. The inhabitants were relocated in another part in thearea (personal communication, MAWR of® cials).

Government intervention is not likely to solve the problem of over-exploi-tation, at least in the foreseeable future. The Government lacks the properinstitutional arrangements and management instruments to control aquiferdepletion. Thus, a non-governmental approach was investigated and is reportedin this paper. The extent of groundwater depletion in the Sa’dah Plain wasreviewed and a strategy to control it was proposed. A groundwater ¯ ow modelwas used to analyse some of the characteristics and consequences of depletionand the physical aspects of the control strategy.

Hydrogeology of the Sa’dah Plain

This section mainly draws on the two previous studies by YOMINCO/TNO(1983) and DHV (1992). The YOMINCO/TNO study investigated the waterresources of the area. The major activities were a geophysical survey, a wellinventory and aquifer tests. The DHV study in turn was based on the technical® ndings of that of YOMINCO/TNO with an update on the well inventory.However, DHV investigated other aspects related to water management issues,such as socioeconomic aspects.

In the Plain, regional uplift, block faulting and volcanic activity occurredduring the Tertiary Period in association with the Red Sea rift system. Thesetectonic activities resulted in horsts, grabens, faults and fractures that aregenerally aligned north-north-west to south-south-east and north to south. Thedominant structure in the area is the down-thrown graben of the Plain ® lledwith sedimentary rocks; among them are the Paleozoic sandstones (Wajidsandstones) that are probably dissected by numerous faults of different orienta-tions, forming rock blocks of different vertical displacement. In the Plain and thesurrounding terrain, the Wajid sandstone is the oldest sedimentary rock (Figure2). The formation consists of deltaic deposits and it is subdivided into two units:the Upper and Lower sandstone units. The age of deposition of the Wajidsandstone ranges from Cambrian to Permian and overlies the Precambrianbasement rocks in an approximately horizontal bedding plane. The Lower Wajidsandstone is of Ordovician age and comprises yellow to brownish coloured,cross-bedded, medium-to-coarse grained quartz sandstones, locally interbeddedwith quartizic ironstones. At the contact with the basement a thin layer of basal


Figure 2. Hydrogeological map of the Sa’dah Plain.

conglomerates is exposed. The Upper Wajid sandstone of Carboniferous toPermian age also shows a massive depositional environment and consists ofcross-bedded, light-coloured quartz sandstone and intercalations of clay, silt andmud balls. Outcrops of the Wajid sandstone are dominant north and east of thePlain. Elsewhere in the Plain, it is overlain by the alluvial unconsolidatedsediments that vary in thickness from 10 m at the borders to 50 m at the centre.South of the Plain, the sandstone is covered by the Amran limestone (Figure 2).At the borders of the Plain, the mountain belts are mainly composed ofimpervious rocks intersected by alluvial wadi ® lls.

The Upper and Lower Wajid sandstone are considered as one hydrogeologicalunit. As a consequence of tectonic block-faulting, the depth of the underlyingimpermeable basement complex varies between 100± 150 m in the northern partof the Plain and 600± 700 m in the southern part. Groundwater ¯ ow is supposedto take place in the pores of the sandstone matrix; however, both geologicalevidence and the results of some tests point to a contribution of fractures and® ssures to the overall hydraulic conductivity. It seems that the sandstone aquiferis characterized by a hydraulic conductivity of some 0.1± 0.3 m/day, increasedlocally by secondary ® ssures. Transmissivities varied from 20± 400 m2/day. Theaverage porosity of the total Wajid sandstone series is in the range of 5± 10%,while effective porosity might be around 5%. It is possibly a little higher (5± 10%)


in the friable, weathered upper horizons of the sandstone aquifer. Given suchhydraulic properties, the Wajid Sandstone is classi® ed as a moderate aquifer. In1983 piezometric levels varied between 1970 m 1 msl, by the northern borders ofthe Plain, and 1820 m 1 msl at the discharge zone at the mouth of Wadi Marwan.By 1992, the levels had fallen to 1960 m 1 msl and 1800 m 1 msl. Groundwater¯ ows from the north, west, east and south to Wadi Marwan, north-east of thePlain. Impermeable basement underlies the sandstone and is classi® ed as anaquifuge.

The alluvium overlying the sandstone is unsaturated and serves as a rainfallcollector whereafter the ¯ ow in® ltrates into the sandstone aquifer. In the wadisdebouching into the Plain, the alluvium is a system of signi® cance since itreceives recharge from runoff from the surrounding mountains. Characterizedby favourable hydraulic properties, the system is composed of highly permeablewadi ® lls with some lenses with perched water. Parts of the sandstone aquiferoutside the extent of the Plain are covered with the Amran limestone, which hassome very poor hydrogeological characteristics as water ¯ ows through ® ssures,cracks and other secondary openings.

The annual recharge seems to be constant due to the buffering action of thethick alluvial deposits that cover the Wajid sandstone. Besides, in® ltrationthrough the soil pro® le takes place only when there is no soil moisture de® cit.Hence, in cultivated areas where the soil generally has a low moisture de® cit,a higher percentage of rainfall is likely to in® ltrate. In other parts of thealluvium, substantial amounts of rainwater are lost by evapotranspiration.Most of the recharge water comes as runoff from the surrounding mountainswest and north-west of the Plain and in® ltrates through wadi ® lls. This assump-tion is supported by the increase in groundwater salinity from west to east,reaching its maximum at the natural discharge zone in the mouth of WadiMarwan.

With 1100 wells operating, the total amount of abstraction from the sandstoneaquifer was 57 MCM in 1983. The annual gross abstraction rate, mostly forirrigation purposes, increased from about 1 MCM around 1970 to about 80 MCMin 1992, when about 2330 wells were in use in the Plain. Figure 3 explains thehistory of annual groundwater abstraction in the Plain. Doubling the number ofwells within that period, with improved well design and construction, causedabout 30% increase in gross abstraction. The mean well yield measured duringthe 1992 well inventory was 3.3 l/s, about half the 6.7 l/s determined in the 1983well inventory. Owing to the deteriorating productivity of the wells, the netannual abstraction was assumed to top out at 65 MCM beyond 1992. Between1984 and 1986 the annual rate of well drilling in the Plain was at its peak whena total of about 813 wells were drilled. By 1986, the number of wells was almosttwice the number that existed in 1983. Consequently, the rate of pumping musthave escalated proportionally. Abstraction from the aquifer outside the border ofthe Plain, mainly due south, was insigni® cant as few wells tapped the aquifer inthat vicinity.

To formulate a management strategy, a model was set up with the followingobjectives:

· to estimate annual natural recharge to the sandstone aquifer;

· to analyse groundwater depletion;

· to simulate the effects of proposed strategies.


Figure 3. Growth in annual abstraction in the Sa’dah Plain.

The thickness of the Wajid sandstone, which was assumed to be one aquifer,varied between 200 m and 700 m, covered by a thick dry alluvium, varying indepth between 10 m and 50 m. The aquifer is mainly uncon® ned, except forsmall parts in the south and the north-west where the aquifer is con® ned by theAmran limestone. It is assumed that primary pores and secondary fractures andjoints are very well developed in the sandstone so that the aquifer can beapproximately simulated using a porous medium approach. Therefore, thewidely applied groundwater model code MODFLOW (MacDonald & Harbaugh,1988) was employed to simulate groundwater ¯ ow in the aquifer. The simu-lation of the heads was over an annual scale from 1978 to 1992 since a strategywould be designed for several years with overall regional objectives. The modelwas calibrated ® rst by adjusting the values of the hydraulic conductivityto produce the groundwater head contour pattern of the year 1978 as thesteady-state situation.

Using the simulated steady-state heads of 1978 as the initial condition, atransient model was calibrated by mainly adjusting the storage coef® cient andthe recharge rate such that the simulated heads ® tted the measured groundwaterheads of 1983 and 1992, and the historic records of six observation wells. Anannual recharge rate of 6.5 MCM was an output by the calibrated model as partof the water-balance calculations. Recharge was estimated at 10 MCM byYOMINCO/TNO (1983) and 7.2 MCM by DHV (1992).

Extent of Groundwater Depletion

A decline of groundwater level that varied between 0.5 m and 4.5 m wasrecorded between 1983 and 1984 (Danikh & Van der Gun, 1985). Over the wholePlain the average was 1.5 m. In 1991± 92 the average groundwater decline wasreported to be 5.6 m over the whole Plain. An average of 40 m was estimatedbetween 1983 and 1992 (DHV, 1993a). Figure 4 shows the hydrographs of twomonitoring wells that were installed in 1984. Well WRAY1 is located in themiddle of the Plain, while WRAY2 is located close to the edge of the Plain at the


Figure 4. Hydrographs and ® tted trends for WRAY1 and WRAY2.

recharge zone (see Figure 2). The last records were obtained in 1992 and 1990 forWRAY1 and WRAY2, respectively. By performing a time-series analysis on themonthly readings, a trend was ® tted for each series at 95% con® dence level(Figure 4). Nonetheless, the series of WRAY1, with 108 periods of one montheach, was divided into two parts. The ® rst part consisted of 24 periods. Itimplied that the response of the aquifer to the hydrological stresses, mainlypumping, experienced a steeper trend as the rate of pumping increased in 1986.The annual rate of well drilling was at its peak during that period.

Few seasonal variations were observed in the series of WRAY1 as comparedwith WRAY2, indicating that the effects of depletion are stronger at the middlethan at the recharge zone. These results also provide additional support to theassumption that recharge mainly comes from the wadis at the edge of the Plain.In Figure 5 the fall of piezometric levels between 1978 and 1992 is shown for anorth± south cross section in the Plain. Figure 6 shows a contour map of thespatial extent of depletion. Values varied depending on the abstraction intensi-ties and the relative recharge locations. Declines were most pronounced aroundSa’dah Town, where abstraction intensity was higher than other parts of thePlain. Further north, declines were noticeable around the population centres ofAl-Talh and Dahyan.

One of the consequences of groundwater depletion is the reduction of thesaturated thickness of the Sa’dah sandstone aquifer, leading to increased pump-ing costs and ultimately abandonment of wells. By using the results of the modelsimulations the diminishing volumes of the saturated sandstone were calculatedfor different years (Figure 7). In 1983 depth to groundwater was between 20 and40 m below ground surface over most of the Plain (Van der Gun, 1985). A rangeof depths of 40 to 80 m was observed in most parts of the Plain in 1992 (DHV,1994). However, depths exceeded 90 m in the same year in areas west of Sa’dahTown. In the area between Al-Talh and Dahyan, north of the Plain, groundwaterdepth was reported to be more than 80 m. Another consequence was the changein water quality. Change in water quality due to increased salinity was observed(average EC from 750 m S/cm in 1983 to 950 m S/cm in 1992) (Van der Gun, 1985;DHV, 1994).


Figure 5. Fall of piezometric levels along section A-A of Figure 2.

Strategy for Controlling Groundwater Depletion

Current Situation

Since certain government policies and development directions often lead todepletion of water resources, changing these policies and directions is often theessential initial step toward sustainability. During the past few decades, theGovernment of Yemen has adopted a country-wide supply-orientated waterresources management strategy to secure the needs for water for differentpurposes. Groundwater was viewed as the natural exploitable resource toinduce socioeconomic development. The aridity of the region did not supportother options. Groundwater resources development has the advantage of scaleover surface-water development. It does not require large-scale projects such asdams, canals and other engineering structures. In comparison, surface-waterutilization requires large diverting and regulating structures along with thetechnical expertise needed to design, construct and operate them. Anotheradvantage was the widespread occurrence of groundwater in the differentregions of the country giving the government a good opportunity to reach outto remote communities with `tangible’ development. In addition, the develop-ment of groundwater resources in any region of the country was accessible bymany competing users with the simple technology of drilling a well. Coupledwith the need for irrigation water to support agricultural development was theneed to satisfy the growing domestic demand for water.

In the Sa’dah Plain modern groundwater development was extensively startedaround 1978. It was mainly ® nanced by Yemeni Nationals in the neighbouringcountries. The objective was to induce immediate’ socioeconomic developmentin the region by expanding irrigated agriculture. The aquifer cannot sustain therate of abstraction. If the situation continues in the Plain with the present totalabstraction rate, the groundwater ¯ ow model predicts that the aquifer will beexhausted by 2032. The fall in groundwater levels under the present unsustain-able conditions was simulated by the model shown in Figure 8. Water scarcityin the region will then be augmented by aquifer depletion leading to the collapse


Figure 6. Decline in groundwater levels from 1978 to 1992 according to thecalibrated groundwater model.

of the rural agricultural economy and the outmigration of inhabitants, probablyto the other intermontane plains. Owing to high abstraction levels, aquifers inthese areas are already under tremendous stress and cannot support additionaldemand. The situation in the Sa’dah Plain, and in many other intermontanegroundwater basins in Yemen Highlands, gives rise to the question of theviability of groundwater-irrigated agricultural development in the region. Thenational environmental and social costs may surpass the bene® ts. Therefore,in¯ uencing demand becomes the most important measure in the transitionalprogression towards sustainability.

Current Institutional Arrangements

Currently, the major responsibility of administering groundwater resources inthe Plain lies mainly with the Ministry of Agriculture and Water Resources(MAWR). Through its local agency, MAWR issues well-drilling licences andsupervises activity in the ® eld. Licensing is required by a Governmental Decreethat has the power of a by-law. Water resources planning and management isnot practised by MAWR according to the strict de® nition of the term. Watercomes in as the main input in agricultural production. Expansion of agricultureis the goal of MAWR. With the advent of the National Water Resources


Figure 7. Diminishing volume of saturated sandstone as calculated by thecalibrated groundwater model.

Authority (NWRA) in late 1995, the name of the Ministry may be changed in thefuture. According to the Presidential Decree that established the Authority, it isthe sole governmental agency responsible for studying, planning and managingwater resources and the formulation of water resources policies and develop-ment strategies at the national level. It is supposed to replace the previous HighWater Council which did not have much success. In spite of that, it is still a stifftask to conceive, formulate and implement national strategies to control aquiferdepletion, let alone local strategies for rural areas such as the Sa’dah Plain.Another organization involved is the Local Council for Cooperative Develop-ment (LCCD), which is in charge of domestic rural water supplies. Furthermore,parts of Sa’dah Town are supplied by the National Water and SewerageAuthority (NWSA). Finally, there is the General Authority for Rural Electricityand Water (GAREW), whose main responsibility is the design and constructionof domestic water supply schemes for rural areas. Although all these organiza-tions rely on groundwater to deliver their services, no coordination existsbetween them. In the future, NWRA is supposed to achieve such coordinationas a result of its activities. The Water Law, the major management instrument,is still at the draft stage. Absence of the Water Law impedes the Government’sability to intervene at the local level. Allegiance of the local inhabitants to thetribal system is so strong that the Government relies on tribal leaders (sheikhs)for matters of political relevance to the area. Even if legislation exists, it will takea long time to overcome the adherence of the local inhabitants to the customarytribal law. It stands to reason that taking advantage of the existing sociopoliticalforces to confront the water crisis can be an alternative to the minimal localof® cial institutional arrangements for water resources management.

Water Demand Management

The case of the Sa’dah Plain is a speci® c example of all the other YemenHighland plains where the situation requires investigation of the possibilities to


Figure 8. Decline in groundwater levels 1978± 2020 under present conditionsaccording to the calibrated groundwater model.

control demand. Demand control is the ® rst stage in a strategy of sustainableutilization of water resources. In view of the identi® ed adverse effects ofgroundwater resources development in the Plain, the following demand man-agement objectives may be speci® ed:

· improving the irrigation ef® ciency;

· improving allocation of groundwater resources for agricultural and domesticuse;

· postponing new borehole construction by ef® cient use of available water;

· moving toward sustainable groundwater development.

The improvement of irrigation ef® ciency is the most important measure that willdramatically in¯ uence the demand for groundwater. Total irrigation ef® ciencywas estimated to be about 41%. Conveyance ef® ciency was assumed to be 75%since more than 50% of irrigation water is conveyed by pipes. The rest isconveyed by unlined ditches. As for application ef® ciency, it was about 55%owing to the absence of irrigation scheduling and poor levelling of ® elds (DHV,1994). Thus, at farm level a great margin of improvement is required. Because ofthe aridity of the Plain, evaporation losses must be very high. Therefore, allirrigation water should be conveyed by pipes.

Conjunctive use of groundwater and spate water should be implemented at all


possible locations. Traditional spate-diversion structures should be improvedand modernized. By making more spate water available for irrigation, farmerswill reduce groundwater pumping. Furthermore, the yield of the rainfed agricul-ture, which is about 50% of total agricultural land (DHV, 1994), should beimproved.

Historically, all over the country, variable water fees were levied only onsurface water users (spate irrigation) depending on their location on the convey-ance network. The objective was to recover both capital and operation andmaintenance costs of the diversion structures. To ensure equity and sustainabil-ity of water resources management, farmers upstream paid more than down-stream farmers (Bamatraf, 1991).

As for groundwater, in former times the sustainable use of the resource andthe established water rights did not imply any social costs. Deep wells did notexist and groundwater mining was not practised. Shallow wells were the mainsource of groundwater. Groundwater abstraction was controlled by naturalrecharge mechanisms, achieving physical sustainability. The present situationis different and charging groundwater users becomes a necessary conservationmeasure. Externalities that result from lowering groundwater levels must beconsidered and assessed. Quantifying such externalities enables the managinginstitutions fairly and effectively to in¯ uence the user group causing theexternalities. Drilling new wells and deepening existing wells must be prohib-ited. Diversifying away from irrigated agriculture must be planned for andpriority must be given to domestic use. On the other hand, subsidizationof water-saving irrigation equipment should be implemented and certaincropping patterns should be discouraged (especially qat!1). Of course, imple-menting all these and other possible measures requires proper institutionalarrangements.

Proposed Institutional Arrangements

Historically, the Yemenis have devised various water management instruments.Structures for spate-water diversion for irrigation were constructed on manywadis. In the framework of the customary law rules were set to distribute tasksand costs of management. Traditionally, development of spate irrigation wasessentially a cooperative venture which was closely related to the existing socialstructure in the wadi area. A set of rules for charging bene® ciaries wasestablished. Since ® elds upstream obtained more water than those downstream,upstream ® elds paid more than the ® elds located downstream. Farmers used tohire `water masters’ (wakil) for each wadi to resolve disputes related to waterrights and to supervise the maintenance of water works. Disputes on (spate)water were settled within the traditional system of tribal customary law,administered by the water master or a committee of village sheikhs or digni-taries who belong to the tribes of the litigators. Guided by customary law as apowerful management instrument, people have managed for generations tosolve the problems of spate irrigation. This system can be improved by theintroduction of modern methods and technology. Since groundwater-irrigatedagriculture is a somewhat modern practice in the country, little traditionalexperience has accumulated.

The absence of a water law in Yemen is becoming a priority issue that makesdiscussions about groundwater management merely theoretical. Drilling a well


without a licence is not punishable by law. Neither NWRA nor MAWR can takea farmer to court for doing so since, according to the law, no wrongdoing hasbeen committed. If the Government decided, say, to prohibit deepening wells,the decision could be contested by any private citizen. Any judge at the lowestlevel in the judicial system would rule out such a decision as being a violationof the constitutional rights of the citizens, i.e. their property rights.

According to the Sharia’t (Islamic Law), water in its natural state is commonproperty and proportionment of the resource must be equitable. This principalwas incorporated in the Draft Water Law of Yemen (NWRA, 1996). Neverthe-less, according to customary law, a well and the water in it are the privateproperty of the person who dug the well (Frederick, 1993). The owner of the wellcannot prevent users from satisfying their human needs. In view of the aquiferconcept this traditional rule may not be applicable any more. Co-dependence ofwells tapping an aquifer is an established fact. In addition the rule wasintroduced when depletion was not a serious threat to society. This aspect ofcustomary law therefore mitigates against the sustainable development of anaquifer. Another principle of the Sharia’t stipulates that preventing damagetakes precedence over accruing bene® ts. Thus, the concept of user right ratherthan property right may be closer to re¯ ecting the co-dependence of wellstapping an aquifer.

In the late 1960s, the cooperative approach was adopted to deal withdevelopment issues throughout the country. To institutionalize this approach,Local Councils for Cooperative Development (LCCDs) were initiated. TheLCCDs are semi-of® cial organizations whose members are elected by theinhabitants. The basic idea, which originated in the rural districts, was toencourage people in the local communities to cooperate to solve their develop-ment problems. Later on, speci® cally in the 1970s, a law was enacted toregulate and support the LCCDs. For every 500 inhabitants in every district arepresentative is elected for ® ve years. An executive body of ® ve, seven or ninemembers is then elected by the representatives. In addition, a chairman, asecretary-general and treasurer are elected (DHV, 1994). The members of theCouncils are the local leaders, dignitaries and sheikhs. Thus, the structureprovides for the social forces and minimizes, or probably eliminates, unneces-sary con¯ icts within the tribal system. As regards ® nancial affairs, they cancollect different fees as stipulated and regulated by the law. The responsibili-ties of the Councils encompass rural development services such as roads,schools, health centres, tree nurseries, planting of forest trees and domesticwater supply. The LCCDs hire professionals in the different disciplines relatedto the tasks to be achieved. Some of them are permanent employees, such asengineers and accountants. The LCCDs no longer play a signi® cant role inagricultural development or water management. The farmers wish them tobecome involved again in solving problems. The projects of GAREW areexecuted in collaboration with the LCCDs, who undertake operation andmaintenance later. Under certain circumstances, the Councils collect funds forconstruction of new water-supply projects. They constitute the most favour-able institutional framework for involving the main stakeholders in groundwa-ter resources management, since the goal of the LCCDs is to inducesocioeconomic development in rural areas. In the Sa’dah Plain, the limitingfactor to development is water. Therefore, LCCD activities should be centredaround water resources management.


Towards a Sustainable Strategy

Sustainable water resources management is a multidisciplinary activity.Nonetheless, since the main constraint in the case of the Sa’dah Plain isgroundwater availability, the main theme of the strategy must concentratearound this topic. Thus, the trigger for water resources management in theSa’dah Plain is the adverse effects of mining the only aquifer in the Plain.However, ® rst, the strategy must be socially acceptable, and deal closely withthe social structure and prevalent societal norms. Total involvement of stake-holders is necessary. Second, the strategy should be physically sustainable. Theannual recharge to the aquifer is the total possible abstracted volume underphysical sustainability. Third, it is not possible to keep up the sustainableconditions without proper institutions. Institutional sustainability implies thecapacity of the involved entities to continue to run the management process afterestablishment. The extent to which stakeholders are involved in managing theresource determines the institutional sustainability of the strategy. Institutionalarrangements should be considered in the context of the indigenous sociopoliti-cal structure. Fourth, the strategy should aim at ® nancial sustainability of themanagement activities. If the stakeholders accept the proposed managementarrangements, they will be willing to share in ® nancing. Recent experiences inthe rural areas of Yemen have shown that people contributed to building ruralroads. Later on, they continue to contribute to road maintenance. Sanctions fornon-compliance and penalties for misuse must be translated into monetaryvalues. Therefore, a strategy achieves institutional sustainability by the degree ofstakeholder involvement, i.e. direct participation in decision making in allmanagement issues. Finally, as noted before, customary law and traditionalsocial forces are the chief management instruments to assure conformity withand implementation of the strategy. Since depletion is the main issue in thewater management strategy, groundwater levels were adopted as the principalcriterion in judging physical sustainability.

The proposed strategy was developed by taking into account the constraintsof the problem domain. These constraints are:

· socioeconomic development and opportunities for future generation;

· limited possibility for developing additional supplies;

· decline of groundwater levels.

Thus, the decision variables are mainly controlled by the problem of depletion.Therefore, four important characteristics of any considered strategy are linked tothe management objectives:

· control of abstraction;

· change in cropping pattern;

· water demand management (irrigation ef® ciency);

· institutional arrangements.

The assumed time horizon of 25 years, starting in 1996 and extending to 2020,for the formulated strategy was assumed for two reasons:

(1) The recent socioeconomic development started in the early 1970s. Thesituation of over-exploitation of groundwater is related to that. Reversing thenegative effects may take at least the same time.

(2) The population of the Sa’dah Plain will, roughly, double by the year 2020.


Figure 9. Decline in groundwater levels 1978± 2020 under sustainable strategy.

Under this strategy, water demand management will be the major tool toin¯ uence water use, irrigation ef® ciency improvement to 75% being the mainmeasure. The net abstraction will have to be reduced by about 11% per annumstarting in the year 2000. In other words, an `abstraction quota’ has to beadopted. By the year 2020, total net annual abstraction will balance the annualnatural recharge. In addition, diversifying away from irrigated agriculture willhave a marked effect on reducing groundwater abstraction. Based on thatassumption, a change in cropping pattern will take place in response to thediminishing rate of abstraction. Under the conditions of this strategy, thepiezometric levels in the aquifer were simulated as shown in Figure 9.

The most important characteristic of this strategy is the institutional arrange-ments. The responsibilities of MAWR on groundwater should be transferred toLCCDs. At present the councils operate under the supervision of the Ministry ofLocal Administration. For the purpose of water resources management, theymay be supervised by NWRA. The in¯ uence should be in a manner thatincorporates their activities in the national water resources strategy. Manage-ment of groundwater resources by the LCCDs is especially suited to the Sa’dahPlain since the aquifer is secluded, and no inter-regional con¯ icts are possible.Hence, the powers of the Government are not required to resolve any inter-regional con¯ icts. Another reason is the homogenous social structure (tribalsystem) of the inhabitants (the stakeholders). In addition, democratic control is


provided for by the bene® ciaries as the main stakeholders (the electorate). Theapproach is based on cooperative action at grass-roots level. They can adapt, andalready are adapting, to the traditional local leadership arrangements, whichsimply re¯ ect the local sociopolitical structure. Another advantage is building onan existing institution which is more feasible at a lower political and economiccost (World Bank, 1993). The concept of the lowest appropriate level of decisionmaking is realized. Furthermore, customary law would play an important rolein organizing groundwater use.

The scope of their role needs careful design and may be delineated as follows,but not necessarily limited to these activities:

· decisions on annual abstraction quotas;

· implementing and monitoring abstraction levels in the different districts in thePlain;

· groundwater-level monitoring;

· supervision of drilling activities;

· dispute resolutions;

· local awareness campaigns;

· collection of water fees;

· promoting water-demand measures;

· incorporating groundwater irrigation and spate-water irrigation practices;

· introducing sustainable groundwater management principles into the custom-ary law;

· helping create a sense of collective ownership and consciousness about theresource;

· coordinating domestic water supply schemes with GAREW and NWSA;

· coordinating rainfed agriculture research and extension with MAWR;

· coordinating the national water strategy with NWRA.

Concluding Remarks

Government intervention is not likely to solve the problem of over-exploitationin the Sa’dah Plain, at least in the foreseeable future, owing to the lack of properinstitutional arrangements and management instruments. Thus, a non-govern-mental approach must be sought at a grass-roots level to confront the crisis,especially in rural areas where irrigated agriculture is the major economicactivity. Besides, it is the local communities that would bear the burden oftransformation to a sustainable solution. To redeem the situation, groundwaterutilization must be brought back to sustainable levels by following a strategythat would reverse the current trend of over-exploitation. Under this strategywater-demand management would be the major tool to in¯ uence water use. Anabstraction quota has to be adopted to reduce net abstraction by about 11% perannum starting in the year 2000 to balance the annual natural recharge by theyear 2020. In addition, diversifying away from irrigated agriculture would havea marked effect on reducing groundwater abstraction. Based on that assumption,a change in cropping pattern would take place in response to the diminishingrate of abstraction. Institutional arrangements are a prerequisite for a sustainablestrategy to be translated to actions on the ground. Customary law would playa big role in implementation and enforcement. According to this strategy, theresponsibilities of the Ministry of Agriculture and Water Resources on ground-


water would be transferred to the Local Councils for Cooperative Development(LCCDs) as possible candidates for a grass-roots-level organization.

Note

1. A plant whose leaves are chewed to induce a stimulating effect.

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A strategy for controlling groundwater depletion in the Sa'dah Plain, Yemen

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